The present invention relates generally to a mobile cleaning apparatus having enhanced pickup efficiency and dumping or disposal capabilities relative to other known machines of this type.
In view of the recent pnenomenon of huge shopping centers and malls having a contiguous paved parking area for customer convenience comprising many acres of land, it has become necessary to utilize mechanical means to clean the dirt and debris from the vast stretches of paved acreage. Yet, it is believed that previously known mobile cleaning apparatus have all suffered from various inadequacies relating to their speed and efficiency. These inadequacies inherent in previously known cleaning apparatus when viewed in light of the great capital investment typically required to construct such a machine, have created a need for a mobile cleaning apparatus which can be efficiently operated at high surface speeds and which possesses the capability to quickly and easily dump collected debris into an assortment of standardized, free standing trash bins such as are typically found at modern shopping malls and the like.
Mobile cleaning apparatus have previously been known utilizing either a vacuum, or a vacuum in combination with positive air pressure to clean a surface area. Typical of this type of apparatus is U.S. Pat. No. 1,704,043 issued to Green which discloses a suction street cleaner. This cleaner utilizes both positive air pressure and vacuum currents supplied to a pickup head for cleaning a street surface, but the device apparently does not possess the capability to dump the collected contents into a remote free standing trash bin or garbage collector typically found at the site of large parking lots. The pickup head, due to its diamond-shaped configuration having the pressure duct located at its leading point, would tend to push light trash and dirt away from the head in the fashion of a snow shovel as opposed to the present invention which is designed to trap debris within the pickup head so as to facilitate vacuum removal. U.S. Pat. No. 3,744,653 to Jensen discloses a lift dump vacuum apparatus which depends solely on a pneumatic vacuum head to remove dirt and debris from a surface area. The apparatus is therefore believed to be inherently less efficient in cleaning a parking lot than the apparatus of the present invention. Because dirt and debris communicate directly with the fan blades, there is considerable wear and deterioration of the air blower. Also, the dumping means disclosed by the Jensen patent comprises a hopper which is upwardly and rearwardly raised by hydraulic rams. The hopper is hydraulically tilted downwardly and its back door opened to allow the contents to slide downwardly under the influence of gravity. This apparatus is believed to be inherently less efficient in dumping accumulated debris, particularly mud and the like, than the present invention which utilizes a hydraulically actuated bottom door in the collection hopper means. Furthermore, the apparatus disclosed in Jensen requires a support arm and pad adjacent the rear end of the vehicle chassis for stabilizing the apparatus when the collection hopper is raised--a structure which is unnecessary on the sweeper according to the present invention.
U.S. Pat. No. 3,662,427 to Hanna discloses a vacuum-pressure apparatus for sweeping exterior areas, comprised primarily of a conventional open bed truck having a pressure and vacuum system mounted on its bed. The patent discloses a fixed collector compartment which cannot be raised for emptying into a trash bin, and a transversely mounted, rectilinear pickup head having a pressure duct at one end and a vacuum duct at the other. This pickup head configuration attempts to force dirt and debris dislodged by the air pressure supplied at one end of the pickup head in a direction perpendicular to the axis of travel of the vehicle to the suction outlet at the opposing end of the pickup head. Hence, the sweeper must move at a relatively slow speed.
An air sweeper apparatus is known to be manufactured under the trade name TYMCO (Model 210) having a hopper which pivots upwardly for dumping in a similar fashion to a dump truck bed and utilizing a transversely mounted pickup head with a laterally spaced-apart pressure port and vacuum port for collecting debris. The machine includes a fan positioned outside the hopper and is believed to be substantially less efficient in use than the apparatus of the present invention.
Other street and parking lot cleaning equipment of interest are disclosed in U.S. Pat. No. 3,406,424 to Rush, U.S. Pat. No. 3,105,991 to Oberg and U.S. Pat. No. 1,181,279 to Williams. These patents disclose cleaning apparatus which utilize air pressure and suction in combination with a cleaning brush, and vacuum suction sweepers in combination with cleaning brushes. These devices are believed to be inherently less efficient and practical than the apparatus of the present invention for the reasons outlined above, among others.